Janet Daley was born in America where she began her political life on the Left as an undergraduate at Berkeley. She moved to Britain (and to the Right) in 1965 where she spent nearly twenty years in academic life before becoming a political commentator: all factors that inform her writing on British and American policy and politicians.

Cameron gets angry about personalities not principles

My colleague James Kirkup makes the point that David Cameron's little burst of anger ("muttering idiot") at Ed Balls delighted his own backbenches during a rough PMQs, but but could look like a dangerous loss of self-control to the wider audience at home. True enough. But even more alarming perhaps is that Mr Cameron never seems to manifest any enraged frustration about – oh, say, the terrible plight of ordinary struggling taxpayers, or the intractable contradictions of the European economy, or any of the other hopelessly depressing realities of political life. The most we ever get is a solemn pronouncement of urgent concern, or a patronising scolding of other world leaders (Mrs Merkel) for not taking "decisive action" in ways that are usually, in fact, unavailable.

And all of those manifestations of dissatisfaction have a stage-y, rehearsed sort of quality about them: there is none of that visceral, heated authenticity which rises to the surface when Mr Cameron is faced with a genuinely annoying personal adversary. So the question is – and it is one being asked by almost every Tory politician I meet these days (including some who are very high up indeed in government and in the party heirarchy) – does Mr Cameron feel really, really strongly about any principle at all? Strongly enough to give in to a full-throated, emotional outburst of the kind that can clearly be provoked in him by a man who is behaving in an irritating way? Is there any idea or value to which the Prime Minister has such a strong attachment that a threat to it could cause him to lose his temper? If there is – and he did – then that display of rage might be a positive asset to him politically.